Home Automation - High Voltage side

[dunny]

When we build the extension at the rear of the house I would like to introduce some Home Automation including control of lights (ON/OFF/DIM), control of some specific outlets (e.g. lamps, fans) plus some audio visual stuff.

I am happy with the low voltage side of what is needed but I am trying to understand what the high voltage side entails. Whilst I wont be fitting it myself I want to understand what is needed.

For the lighting I understand there are DIN mounted dimmer modules that can be fired by the 5v outputs on the microcontroller. What are the most common ones in the UK? Can one dimmer module cover more than one circuit?? Is it possible to, for example, switch on individual LED lights in a circuit (e.g. 10 LED lights but only want to switch on lights 2 4 6?

For controlling specific outlets I understand there are DIN mounted relays that can also be switched by the 5v outputs of the microcontroller (I read in here somewhere it is better to use 12v for relays due to EMF issues??) - again what are the most common and would there normally be one relay per outlet that requires controlling? Could I not use a small relay board that can be connected to the microcontroller board (I did this during some prototyping) instead of DIN mounted relays.

Is all of the low voltage stuff placed in a separate enclosure and does the wiring from the LV side to the HV side need to be of any particular rating?

I am expecting that the main cabling would all be in a star configuration back to the CU but is it still possible to retain traditional light switches (or similar) with this set up??

I want all the LV side to be cabled rather than wireless and will probably use CAT6 and possibly POE for the microcontroller boards.

Thanks for any pointers.

D

 

[JohnW2]

Someone's almost bound to take you to task over this so, to get it out of the way, let me tell you that in electrician-speak (some will say 'the only correct terminology') 'Low Voltage' is 50V-1,000V AC (or 120V-1500V DC) and "High Voltage" is above 1,000V AC (or above 1,500V DC). What you are referring to as "Low Voltage" is what they would call "Extra Low Voltage".

Having explained that to you, I hope there will be no debate/argument about your use of terminology!

Kind Regards, John

 

[EFLImpudence]

Stop criticising the posters.

 

[JohnW2]

Stop criticising the posters.

As I'm sure you actually realise, the whole point of my post was to 'inform' the OP before anyone had a chance to start criticising, teasing or intimidating him. If they try that now, they can hardly hide behind the excuse that they are 'educating'!

Kind Regards, John

 

[EFLImpudence]

I don't understand why you telling them is "informing" while anyone else doing it is "criticising, teasing or intimidating and hiding behind the excuse of educating".

 

[JohnW2]

I don't understand why you telling them is "informing" while anyone else doing it is "criticising, teasing or intimidating and hiding behind the excuse of educating".

If they did it in the same way that I just did, then it would be just as much "informing" as I was. However, that's not how some people do it (and I forgot to include 'sarcasm' in my list!). However, lets not litter the thread with this discussion before the OP gets any helpful response to the questions he wants answered.

Kind Regards, John

 

[dunny]

So, now that is out of the way

Any advice please??

D

 

[JohnW2]

For the lighting I understand there are DIN mounted dimmer modules that can be fired by the 5v outputs on the microcontroller. What are the most common ones in the UK? Can one dimmer module cover more than one circuit?? Is it possible to, for example, switch on individual LED lights in a circuit (e.g. 10 LED lights but only want to switch on lights 2 4 6?

I'm not sure that I fully understand, including what you mean by "more than one circuit". Within the limitations of its capabilities/rating, a dimmer can control anything that is connected to it.

For controlling specific outlets I understand there are DIN mounted relays that can also be switched by the 5v outputs of the microcontroller (I read in here somewhere it is better to use 12v for relays due to EMF issues??) ...

12V is probably more common. I'm not sure what you mean by "EMF issues", but using 12V relays would obviously result in lower currents. If you wanted to use 12V relays, you could obviously use 'primary' 5A 5V relays, fed by your microcontroller, to switch a 12V supply which fed 12V relays.

.... would there normally be one relay per outlet that requires controlling?

I would have thought so.

Could I not use a small relay board that can be connected to the microcontroller board (I did this during some prototyping) instead of DIN mounted relays.

In general, you could theoretically use any relays which were rated for the voltage/current to be switched. One problem with using PCB-mounted relays is that it would involve both 'Extra Low Voltage' ("ELV" = 5V, 12V or whatever) and mains voltage being present on the same PCB, which creates issues of safely/adequately isolating them from one another.

Is all of the low voltage stuff placed in a separate enclosure and does the wiring from the LV side to the HV side need to be of any particular rating?

As above, the requirement is for adequate/safe isolation between the two types of voltage. To some extent you can achieve that by having the two in separate enclosures - but the relays are, by definition, one place where the main and ELV voltages have to exist in close proximity, within the same enclosure.

Hope this helps a bit.

Kind Regards, John

 

[stillp]

you could obviously use 'primary' 5A relays

Did you mean 5V relays John?

 

[securespark]

[giggle]
Someone's almost bound to take you to task over this so, to get it out of the way, let me tell you that in electrician-speak (some will say 'the only correct terminology') "A" refers to current and "V" refers to voltage. What you are referring to as "A" is what they would call "V".

Having explained that to you, I hope there will be no debate/argument about your use of terminology!

Kind Regards, Secure.
[/giggle]

 

[EFLImpudence]

 

[JohnW2]

Did you mean 5V relays John?

As you know, I did - I'll correct the typo. Thanks for pointing it out.

Kind Regards, John

 

[securespark]

Uh oh. He's cross with me now...

 

[JohnW2]

Uh oh. He's cross with me now...

Who is - me? If so, I'm not, and I don't see why you should think so!

However, as I said, I think we owe it to the OP not to litter the early parts of this thread with trivia (it's not so bad after an OP's questions(s) have been answered!) - so far, I'm the only person who has made any attempt (and that a not-very-good one) to address some of his questions.

Kind Regards, John

 

[dunny]

Thanks John.

In terms of using 5v relays to switch a 12v supply to the DIN mounted relay, how would this work in practice?

The bit I cant get my head around is what exactly goes between the 5v output of the PCB relay and the 12v input on the DIN mounted relay??

My question regarding the dimmers may be a bit of a naïve one. I thought there may be 'intelligent' DIN mounted dimmer modules that could have, say, three circuits connected and I could send a message to an input that would control a specific load - is there such a thing?

Could anyone point me at the commonly used modules?

Thanks

D